Implementation of dose management system
- Workflow
- Connection of modalities
Data security
- Pseudonimisation of patient data
Uses of a data management system
- Demonstrating compliance with diagnostic reference levels
- Checking (changes in) doselevels
- Investigating outliers
- Obtaining dose information in order to perform risk assessments
IMPLEMENTATION OF A DOSE MANAGEMENT SYSTEM |
Workflow
A modality sends a dose report to the dose management system.
This is either directly or via the PACS system (Picture Archiving and Communication System). The dose management system processes the report and makes the data available for evaluation.
This is either within the dose management system which is able to present data in graphs or via an export of selected data to a spreadsheet program.
In the case of Sectra DoseTrack,
the dose management system in use in Bravis Hospital,
the dose reports are sent to the PACS which forwards the reports to the DoseTrack gateway,
which is a server within the hospital. This server forwards the dose reports to a server in Sweden,
where all data is stored and made available for evaluation and to produce reports.
Connection of modalities
The following issues were encountered when connecting modalities to the dose management system:
- Not all modalities were standard equipped with an option to export dose information in DICOM RDSR format (radiation dose structured report).
This extra option had to be purchased by the vendor in some cases to be able to collect dose information.
Alternatives, such as dose information in the DICOM header of an image or Secondary Capture,
which is an image containing a screen capture of a dose report,
cannot be processed directly by our dose management system.
- Not all modalities have the software option to send dose data to another destination (such as a dose management system) as the image data which goes to the image archive.
If the modality does not have this option,
the PACS should be instructed to forward the dosereports to the dose management system.
- Furthermore it is also important that the modality is able to send dose reports automatically. This reduces the administrative burden on staff.
Due to the fact that Sectra DoseTrack is a cloud solution,
the dose data is sent to a server outside of the hospital (the country even),
patient data security was a point of attention.
First a dedicated and safe connection was made to the external server.
Furthermore Bravis Hospital chose to use pseudomisation of the patient data on the gateway server.
So in case of a data breach of the external server,
data cannot be traced back to individual patients.
For the hospital however,
the data can be combined with data stored in other systems (such as accession number in PACS) to trace the data back to individual patients.
USE OF A DOSE MANAGEMENT SYSTEM |
Diagnostic reference levels
By storing all dose reports from for example all examinations on all CT systems within the hospital, enough data is acquired to establish local diagnostic reference levels (DRL's).
In the Netherlands,
national diagnostisc reference levels have been established for mammography,
radiography,
computed tomography and diagnostic fluoroscopy examinations.
The method for measuring these values can put an administrative burden on staff.
But by extracting them from the dose management system,
measuring the DRL's is straightforward.
For example the DRL for diagnostic coronary angiography is defined as a dose area product (DAP) of 80 Gycm2 for a patient of 77 kg (achievable level is DAP of 30 Gym2).
This is measured by selecting 20 patients and measuring the DAP and weight and interpolating for a patient of 77 kg.
By using the dose management system,
DAP and weight of 600 patients is extracted,
plotted and interpolated to measure the DRL without administrative burden to staff (Fig. 1).
Checking (changes in) doselevels
The dose management system allows for making quick overviews of dose data,
arranged by for example system,
modality or procedure.
A change in protocol,
for example in case of optimalisation or after a software update,
can easily be checked.
Also comparison of dose levels of the same protocol on different scanners can also easily be done.
An example is shown in Fig. 2.
Investigation outliers
Via the dose management system it is easy to make an overview of all data for a specific examination or procedure code.
Sometimes there are outliers, see for example Fig. 3.
Here data is presented for a periode of 2 months in 2016,
in which a CT abdomen examination had a much higher dose than average.
The examination was investigated and two reasons were found for the higher dose.
First the patient received a multi phase liver scan instead of a standard abdomen scan.
Secondly the patient was very large.
Scan parameters were adapted accordingly which resulted in a higher dose,
which was necessary to obtain an acceptable image quality.
So in conclusion the patient received the right dose even though it was an outlier in the dose management system.
Risk assessment
A data management system is also a great tool in performing risk assessments for exposed workers.
By knowing exactly how much dose is administered to patients,
is it possible to calculate the resulting scattered dose from all these examinations.
This aids in determining the radiation risk for exposed workers.